The Claim

In two healthy adult individuals, daily supplementation with 10,000 IU of vitamin A for approximately 21 days was associated with increased apparent absorption of a subsequent oral dose of [14C]beta-carotene, as measured by urinary excretion over a 30-day collection period, with absorption rising from 57% to 74% in one subject and from 52% to 75% in the other.

Source: Absorption and retinol equivalence of β-carotene in humans is influenced by dietary vitamin A intake Published, JLR Papers in Press, June 1, 2003. DOI 10.1194/jlr.M300116-JLR200

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
24score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

Correlation
1 study reviewed
In plain English

Taking a lot of vitamin A every day for about three weeks might help two healthy people absorb more beta-carotene from their food, based on how much showed up in their urine over the next month.

See the scientific wording

In two healthy adults, daily supplementation with 10,000 IU of vitamin A for approximately 21 days was associated with increased apparent absorption of a subsequent oral dose of [14C]beta-carotene, as measured by a rise from 57% to 74% in one subject and from 52% to 75% in the other over a 30-day collection period.

What the research says

1 study
  1. Study: Absorption and retinol equivalence of β-carotene in humans is influenced by dietary vitamin A intake Published, JLR Papers in Press, June 1, 2003. DOI 10.1194/jlr.M300116-JLR200

    The study gave people vitamin A for 21 days and then checked how well their bodies absorbed beta-carotene. It found absorption improved, just like the claim says.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

Fit Body Science verdict — we translate health claims into clear verdicts backed by peer-reviewed research.

Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.